Physicians throughout California are considering whether to sell their practices to and join or affiliate with an “integrated delivery system” (IDS). IDSs, which are generally hospital-sponsored, include management services organizations (MSOs), accountable care organizations (ACOs), physician-hospital organizations (PHOs) and tax-exempt “foundations.” The decision whether to affiliate or sell and, if so, on what terms, is a complex one. This document discusses the key issues physicians need to consider before making that decision. For a discussion of physician-hospital alignments in general and the antitrust issues they raise, see